Substrate carriers configured for holding multiple hard disk substrates during fabrication and shipping are well known in the data storage device industry. Examples of such prior art carriers are described in U.S. Pat. Nos. 5,921,397; 5,704,494; 4,669,612; and 5,348,151, each of which is hereby fully incorporated herein by reference.
During processing of hard disks using known prior art carriers, a typical quality control practice involves designating one of the disks as a “test disk” for quality control inspection and lot identification. Testing may require the compromise or destruction of the test disk under examination. As a result, the yield of finished hard disks per batch is reduced at least by one disk, and the complexity of disk processing is increased due to post-processing tracking and handling of the designated test disk.
Also, disk processing often involves the baking of the disks at temperatures of up to 300° C. or higher. Consequently, handling of the disk carrier during processing is generally automated. A relatively high degree of precision in carrier positioning is desirable to minimize disk damage and particulate generation from improper indexing of the robotic tooling. Prior art carriers, while offering a generally workable degree of precision in positioning, are still sometimes mispositioned, resulting in disk damage or excessive particulates in the processing environment.
What is needed in the industry is a disk carrier that addresses the above-identified deficiencies in the prior art carriers.